Depends on needs and budget, I have the VU+ Uno 4K (£219 from wos i think now). Has 8 cable tuners and you can install kodi etc. It's a nice box, it's the one I use as main box.
I don't use all 8 tuners at once but it's handy if, like my wife, you record all the soaps etc you don't need to worry about them clashing especially if one ends at 8 and another starts at 8 etc. I also have my H2S using fallback so access the vu+ tuners making the H2s a 2nd cable box.
I've probably used no more than 4 tuners at most at any one time, you may have to speak to your line provider if you plan to use more than 2 or 3 tuners at once to see if they will allow it. You may need a 2nd line or multi-room line.
It's 4K but I don't have a 4K tv at the moment so can't comment on that.